Black widow spider

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The black widow spider (Latrodectus) has a shiny black body with a red hourglass-shape on its belly area. The bite of a black widow spider is poisonous. The class of insects to which the black widow spider belongs, contains the largest number of venomous species known.

This article is for information only. DO NOT use it to treat or manage a black widow spider bite. If you or someone you are with is bitten, call your local emergency number (such as 911), or your local poison center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States.

Poisonous Ingredient

The venom of the black widow spider contains poisonous chemicals that make people sick.

Where Found

Black widows are found throughout the United States, mostly in the South and West. They are usually found in barns, sheds, stone walls, fences, woodpiles, porch furniture, and other outdoor structures.

Symptoms

The first symptom of a black widow bite is usually pain similar to a pinprick. This is felt when the bite is made. Some people may not feel it. Minor swelling, redness, and a target-shaped sore may appear.

After 15 minutes to 1 hour, a dull muscle pain spreads from the bite area to the whole body.

If the bite is on the upper body, you will usually feel most of the pain in your chest.

If the bite is on your lower body, you will usually feel most of the pain in your abdomen.

Home Care

Black widow spider bites are very poisonous. Seek medical help right away. Call the Poison Control Center for guidance.

Follow these steps until medical help is given:

Clean the area with soap and water.

Wrap ice in a clean cloth and place it on the bite area. Leave it on for 10 minutes and then off for 10 minutes. Repeat this process. If the person has blood flow problems, decrease the time that the ice is on the area to prevent possible skin damage.

Keep the affected area still, if possible, to prevent the venom from spreading. A homemade splint may be helpful if the bite was on the arms, legs, hands, or feet.

Loosen clothing and remove rings and other tight jewelry.

Before Calling Emergency

Have this information ready:

Person's age, weight, and condition

Time the bite occurred

Area on the body where the bite occurred

Type of spider, if possible

Poison Control

Your local poison center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

What to Expect at the Emergency Room

If possible, bring the spider to the emergency room. Put it in a secure container.

The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. The person may receive:

Antivenin, a medicine to reverse the effects of the venom, if available

Blood and urine tests

Breathing support, including oxygen

Chest or abdominal x-rays

ECG (electrocardiogram, or heart tracing)

Intravenous fluids (through a vein)

Medicines to treat symptoms

In general, children, pregnant women, and the elderly may need to be given Latrodectus antivenom to reverse the effect of the poison. However, it can cause serious allergic reactions and must be used carefully.

Outlook (Prognosis)

Severe symptoms usually start to improve within 2 to 3 days, but milder symptoms may last for several weeks. Death in a healthy person is very rare. Young children, the very ill, and the elderly may not survive a bite.

Wear protective clothing when traveling through areas where these spiders live. DO NOT stick your hands or feet in their nests or in their preferred hiding places, such as dark, sheltered areas under logs or underbrush, or other damp, moist areas.

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